Question

a runner ran 100 meters in 10.49 seconds. using dimensional analysis and using 3.28 feet per meter and 5,280 feet per mile, how fast did they do this in miles per hour? Please include all multiplication and division steps when you write out the answer

Answer 1

a runner ran 100 meters in 10.49 seconds. using dimensional analysis and using 3.28 feet per meter and 5,280 feet per mile, how fast did they do this in miles per hour? Please include all multiplication and division steps when you write out the answer​

step 1

Convert meters to feet

we have that

3.28 ft ------------> 1 m

so

100 m=100*(3.28)=328 ft

step 2

Convert ft to miles

we have that

5,280 ft ----------> 1 mi

so

328 ft=328/5,280 mi

step 3

Convert sec to hours

we have that

1 h----------> 3,600 sec

so

10.49 sec=10.49/3,600 h

step 4

Find the speed in miles per hours

Divide the distance in miles by the time in hours

so

(328/5,280)/(10.49/3,600)=(328*3,600)/(10.49*5,280)

21.32 miles/hour